1. Field of the Invention
The present invention relates to a portable radio communication apparatus and, particularly, to a radio communication apparatus and a power-saving method thereof.
2. Description of the Prior Art
In general, portable or mobile telephones carried by users are battery-powered. Therefore, it is very important to effectively use the battery power so that the standby or continuous operation time period becomes as long as possible. Therefore, it is desirable that its power consumption be minimized.
To achieve reduction in power consumption, a portable telephone has two operation modes: a normal operation mode and a power-saving mode (which may be called HALT mode, IDOL mode, or STOP mode). When the portable telephone is not used, it operates in the power-saving mode, More specifically, a CPU of the portable telephone controls an intermittently receiving operation to monitor the occurrence of an incoming call and further monitors a key input through a keypad. When an incoming call occurs or any key is depressed, the operation mode is changed from the power-saving mode to the normal operation mode. If no incoming call or no key operation occurs for more than a predetermined time period, then the operation mode returns to the power-saving mode. The time for returning to the power-saving mode varies depending on the maker producing a portable radio telephone.
On the other hand, a liquid-crystal display (LCD),with backlighting has been widely used in a portable radio telephone. Such a backlit LCD improves the LCD screen""s readability but draws more power than an ordinary LCD does. Therefore, reduction in power consumption is an indispensable condition especially for a battery-powered radio telephone terminal having the LCD with backlighting.
To reduce in power consumption, several power-saving methods have been proposed. For example, in Japanese Patent Unexamined Publication No. 9-27844, a portable telephone having a backlight-control function is disclosed. More specifically, the LCD is backlighted when any key input or an incoming call occurs in dark conditions and, after a lapse of a predetermined time period, the backlighting is shut off.
Another portable terminal having backlight-control function is also disclosed in Japanese Patent Unexamined Publication No. 10-23129. In this portable terminal, an interrupt occurs and the LCD is backlighted when any key input occurs at predetermined times of day. After a lapse of a predetermined time period, the backlighting is shut off. If the key input occurs at any time other that the predetermined times of day, then the LCD is not backlighted.
However, the user does not always operate the keypad so as to make a call but just to watch radio conditions or the time of day. Recently, an increasing number of radio telephones have a function of displaying an animated comic character on screen. Therefore, the user frequently operates the keypad to see such an animated comic character. According to the prior arts as described above, such a key operation which is not intended to make a call causes the microprocessor (CPU) to change from the power-saving mode to the normal operation mode. This causes the battery power to be wasted.
An object of the present invention is to provide a radio communication apparatus and a power-saving method which can achieve reduction in power consumption.
Another object of the present invention is to provide a radio communication apparatus and a power-saving method which can perform predetermined operations without the microprocessor changing from the power-saving mode to the normal operation mode.
According to an aspect of the present invention, a portable radio communication apparatus operable in one of a normal operation mode and a power-saving mode, comprises:
an input device having a plurality of keys consisting of a predetermined key and a plurality of general keys;
a first controller for changing an operation mode of the portable radio communication apparatus from the power-saving mode to the normal operation mode when receiving an interrupt signal; and
a second controller for outputting the interrupt signal to the first controller when one of the general keys is operated and starting a predetermined operation without outputting the interrupt signal when the predetermined key is operated.
According to another aspect of the present invention, a portable radio communication apparatus operable in one of a normal operation mode and a power-saving mode, comprises:
a display;
a light for backlighting at least the display;
an input device having a plurality of keys consisting of a predetermined key and a plurality of general keys;
a first controller for changing an operation mode of the portable radio communication apparatus from the power-saving mode to the normal operation mode when receiving an interrupt signal; and
a second controller for outputting the interrupt signal to the first controller when one of the general keys is operated and, when the predetermined key is operated, controlling the display and the light without outputting the interrupt signal such that the light backlights the display and predetermined information is displayed on the display.
The predetermined information may be at least one of the time of day, an electric field strength of a radio receiving signal, and an animated comic character.
The second controller may control the light such that the light backlights the display during an interval that the predetermined key is operated. The second controller may control the light such that the light backlights the display until after a lapse of a predetermined time period from a time when the predetermined key is operated.
The portable radio communication apparatus may comprise a memory storing a plurality of items of information each corresponding to a different predetermined operation. The predetermined information is a selected one of the items of information. The predetermined information is preferably a selected one of the time of day, an electric field strength of a radio receiving signal, and an animated comic character.
The predetermined key is preferably separated from a key matrix mounted with the general keys such that the predetermined key is provided near the display. The plurality of keys may be integrated on a single key matrix.
The plurality of keys may include a function key which is used to switch the second controller between active and inactive.
The input device and the second controller may be integrated to form a key input controller for outputting the interrupt signal to the first controller when one of the general keys is operated and, when the predetermined key is operated, controlling the display and the light without outputting the interrupt signal such that the light backlights the display and predetermined information is displayed on the display.
As described above, according to the present invention, when the predetermined key to depressed in the power-saving mode, the displaying and backlighting operations can be performed by the second controller while the first controller is in the power-saving mode. Therefore, the power consumption can be dramatically reduced.
Further, according to the present invention, the display processing of the predetermined information can be also performed by the second controller while the first controller operates in the normal operation mode. Therefore, some of the display processing load is taken off the first controller, resulting in improved processing speed of the first controller,
Furthermore, in the case of the memory storing necessary data for a plurality of predetermined operations, a selected one of the predetermined operations can be performed independently of the normal operations while the first controller operating in the power-saving mode.